Air con only fills half way?

Rockstarsi · #1 07-01-2015, 04:10 PM

2002 e53 3.0d. Had my air con recharged today. He was planning on putting in 450g of gas but couldn't get more that 265 grams in. It appears only one side was filled. Any ideas why? It's now cooler than it was but no where near as much as it should be ?

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higreenx5 · #2 07-03-2015, 12:14 AM

Did you vacuum it down to 30 inches of vacuum? Are you recharging because of a mechanical failure , because there can be a blockage.

Rockstarsi · #3 07-03-2015, 03:18 AM

The mechanic vavuumed it. The machine he uses creates the vacuum automatically. He suggested there might be a blockage. Question is where

iansanderson · #4 08-04-2015, 07:58 PM

He is probably trying to charge the system on the high-side. Same thing happened to me on my '04. I talked to a master tech at the local BMW dealership and he told me to pull a vacuum for 30:00 (as per the TIS) and fill on low side. Worked for me.

Alika808 · #5 08-09-2015, 01:50 AM

I am wondering if you filled with A/C compressor oil (PAG Oil). It's not same as your issue but something to look at. Sometime ago, I overfilled the A/C compressor with PAG oil and it end up to clogged up the condenser. I end-up to replaced the condenser.

andrewwynn · #6 08-09-2015, 10:33 AM

I topped off my wife's AC the other day and when filling by psi not weight since topping off not complete recharge I had unsatisfactory results when "going by the book" with low side psi. I added more based on the refill kit's ambient based offset and was able to achieve vent output below 40°F

You can't add refrigerant when the compressor isn't running. You didn't explain why it wouldn't take more. It should keep slowly pulling from supply can as long as it's running. It will take on the order of 5-8 minutes as the system slowly pulls additional refrigerant from the low side and compresses into the high side.

My ending gauge readings. Take note of high as well as low side. It is possible the 14 year old system needed a little more than "book" quantities but works perfectly now. Before the recharge the evaporator was freezing up and stopping airflow (stopped blowing clod air after 10 min. ) now it will put out 40° air when 95° outside.

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upallnight · #7 08-09-2015, 01:48 PM

The lower the lowside reading, the colder the evaporator can get, which is fine if you have a freezer since you are not trying to cool warm humid air, but can cause problems on an automotive AC system. If I do top off I would shoot for 36 psi on the lowside. Too much refrigerant will cause the high side to increase which only place extra stress on the system.

Most shop uses a machine that add refrigerant on the high side without the need for the compressor to be running. The refrigerant is added by weight and not by a PSI.

iansanderson · #8 08-09-2015, 09:21 PM

The high pressures on the low side seem to be normal on my 2004. I haven't researched our AC system yet, but I am under the impression the 04-06 models are a high-pressure system. And to the original poster, I used the function "fill using both sides" on the Robinair after 30:00 minutes of vacuum and it filled right up!

ants_oz · #9 08-09-2015, 11:05 PM

Quote:

Originally Posted by upallnight

<snip> The refrigerant is added by weight and not by a PSI.

Exactly right.

The weight of gas will not change, regardless of the pressure it is under. However the VOLUME of gas will change massively dependent on the pressure.

It is the reason why aircons are charged from a state of vacuum. From that point, a specific weight of gas is added, along with lubricants etc as necessary.

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